Changes which take place as a baby develops within the womb can affect sperm production in later life.

Women who smoke or are heavily overweight while pregnant can disrupt there natural development and trigger reduced sperm counts in their offspring, according to a review of the available evidence, carried out by Prof Richard Sharpe of the Queen's Medical Research Institute in Edinburgh.

He found there was no evidence to link exposure to individual chemicals to poor sperm production.

However, exposure to complex mixtures of environmental chemicals, as might be experienced in real life, may have an impact on the development of testicles and lead to low sperm counts in adulthood, the paper warns.

However, more research would need to be done before a link can be fully proven.

Professor Sharpe warns that as humans we are particularly vulnerable to decreased sperm quantity or quality – as fertility among normal males is already "remarkably" low compared to other animals.

He warns that low sperm count caused by developmental problems are potentially irreversible.

According to the review: “The high prevalence of low sperm counts in young men across Europe today is a cause for concern, especially when considered together with the trend for ever-later age for first pregnancy in the female partner (and thus reduced female fertility).

“As this review has shown, evidence for widespread or major effects of individual lifestyle or environmental factors on spermatogenesis in adulthood is largely lacking, whereas there is growing evidence that prenatal exposures of males (reflective of maternal lifestyle or exposures) can have major impact on capacity to produce sperm in adulthood.”

The findings are published in a special issue of the journal Philosophical Transactions of the Royal Society B.